Researchers have proposed an alternative way of making graphene from rice husk. This research, using an ordinary synthetic apparatus and abundant agricultural waste, suggest that low cost graphene materials could now be easily and cheaply synthesized on an industrial scale. Due to its abundance, risk husk has already received much attention as a starting material in generating high-value-added materials such as silica and porous carbon.
Individual graphene sheets and their functionalized derivatives have been used to remove metal ions and organic pollutants from water. These graphene-based nanomaterials show quite high adsorption performance as adsorbents. However they also cause additional cost because the removal of these adsorbent materials after usage is difficult and there is the risk of secondary environmental pollution unless the nanomaterials are collected completely after usage. One solution to this problem would be the assembly of individual sheets into three-dimensional (3D) macroscopic structures which would preserve the unique properties of individual graphene sheets, and offer easy collecting and recycling after water remediation.
By miniaturizing microbial fuel cells, it becomes possible to build miniature energy harvesters that could power lab-on-chip or point-of-care diagnostics devices independent of any external power source. Because micro-sized microbial fuel cells utilize less electrode area and less liquid fuel volume than their macro-sized counterparts, optimizing the electrodes and the fuel sources are the most important factors in designing a micro-sized MFC for maximum power production.
Researchers report the fabrication of flexible, durable, and self-assembled graphene textile electrodes for supercapacitors using a novel wet-spinning approach of ultra large graphene oxide liquid crystals followed by heat-treatment to obtain graphene fibers. The key to producing such fibers and yarns is to preserve the large sheet size even after the reduction of GO while simultaneously maintaining a high interlayer spacing in between graphene sheets. These graphene yarns could lead the way to the realization of powerful next-generation multifunctional renewable wearable energy storage systems.
Graphene is undoubtedly emerging as one of the most promising nanomaterials because of its unique combination of superb properties, which opens a way for its exploitation in a wide spectrum of applications ranging from electronics to optics, sensors, and biodevices. In this Nanowerk nanotechnology primer we summarize recent finding in graphene research and show the breadth of graphene applications in such areas as energy, electronics, sensors and many others.
Recently, nanotechnology researchers have begun to work with graphene foams - three-dimensional structures of interconnected graphene sheets with extremely high conductivity. Since graphene foam possesses a high porosity of close to 100%, this offers the opportunity to use it as a scaffold for other nanomaterials to generate synergistic effects. Now, researchers have fabricated vertically aligned ZnO nanowire arrays on 3D graphene foam and used this electrode to detect uric acid in a reliable statistical level from the serum of Parkinson's disease patients.
Functionalized graphene holds exceptional promise for biological and chemical sensors. In new work, researchers have shown that the distinctive 2D structure of graphene oxide, combined with its superpermeability to water molecules, leads to sensing devices with an unprecedented speed. The team reports the experimental observation of the unparalleled response speed of humidity sensors based on graphene oxide, which are - to the best of the scientists' knowledge - the fastest humidity sensors ever reported.
One item that so far has been missing from graphene's impressive list of physical properties is magnetism. In its pristine state, graphene exhibits no signs of the conventional magnetism usually associated with such materials as iron or nickel. So far, no reports that provide comprehensive evidence for either macro- or nanoscale magnetic phenomena for the ferromagnetism of carbon nanostructures in chemically functionalized graphene structures have appeared in the literature. Researchers have now filled this gap.